In a process for manufacturing a liquid crystal display (LCD) or the like, a plasma processing apparatus such as a plasma etching apparatus, a plasma CVD film forming apparatus and the like is used to perform a predetermined processing on a glass substrate. Conventionally, a capacitively coupled plasma processing apparatus has been widely used as the plasma processing apparatus. Recently, however, an inductively coupled plasma (ICP) processing apparatus capable of generating a high-density plasma has become an increasingly used technology.
In the inductively coupled plasma processing apparatus, a high frequency antenna is provided outside a dielectric window of a processing chamber for accommodating a target substrate to be processed. In the processing chamber, an inductively coupled plasma is generated by supplying a processing gas to the processing chamber and a high frequency power to the high frequency antenna. By using the inductively coupled plasma thus generated, a predetermined plasma processing is performed on the target substrate. A planar antenna having a predetermined pattern is widely used for the high frequency antenna of the inductively coupled plasma processing apparatus. This is described in Japanese Patent Publication No. 3077009.
Recently, a target substrate to be processed has been increased in size. For example, a rectangular glass substrate for use in an LCD is considerably scaled up from about 1500 mm×1800 mm (short side×long side) to about 2200 mm×2400 mm and further to about 2800 mm×3000 mm.
In the inductively coupled plasma processing apparatus, a dielectric window is inserted between the high frequency antenna and the processing chamber. When the target substrate is scaled up, the dielectric window is also scaled up. However, the dielectric window is generally made of quartz glass or ceramic, as described in Japanese Patent Publication No. 3077009.
Since quartz or ceramic is brittle, it is not suitable for the scaling up of the dielectric window. Japanese Patent Publication No. 3609985 discloses a technique for dividing quartz glass in order to scale up the dielectric window.
However, as the target substrate has increased in size markedly, it has become more difficult to apply the technique for dividing the dielectric window disclosed in Japanese Patent Publication No. 3609985.